Interactive Periodic Table - With Spectral Lines
Tests of Big Bang Cosmology
The Big Bang Model is supported by a number of important
observations, each of which are described in more detail
on separate pages:
1. The expansion of the universe
Edwin Hubble's 1929 observation that galaxies were generally
receding from us provided the first clue that the Big Bang
theory might be right.
2. The abundance of the light elements H, He, Li
The Big Bang theory predicts that these light elements should
have been fused from protons and neutrons in the first few
minutes after the Big Bang.
In 1948, Physicist George Gamow hypothesized that all of the
elements might have been made in the hot and dense early
universe. He suggested to his student, Ralph Alpher, that he
calculate this. Alpher did so for his PhD thesis, with Robert
Herman participating in much of the work. Alpher and Herman
found that Gamow was wrong: most elements could not have been
made in the early universe. The problem is with neutron
capture. Neutrons decay in about 10 minutes, and their
density decreases as the universe expands in that time. There
just isn't enough time to keep building up to the heavier
elements before the neutrons are gone. The heavy elements are
made later, in stars. Only the lightest elements are built up
in the early universe. The important prediction that the
cosmic microwave background (CMB) exists, and has a blackbody
spectrum with a temperature of about 5 degrees above absolute
zero, was a by-product of this work.
Fundamental Particle and Interactions
Comparison of Solar Nucleosysthesis and Big Bang Neucleosysnthesis
Solar Nucleosynthesis -- proton-proton chain
pp p + p --> H2 + e+ + v_e 100 q < 0.420 MeV
pep p + e- + p --> H2 + v_e 0.4 q = 1.442 MeV
hep He3 + p --> He4 + v_e 0.00002 q < 18.773 MeV
Be7 Be7 + e- --> Li7 + v_e 15 q = 0.862 MeV 89.7%, q = 0.384 MeV 10.3%
B8 B8 --> Be7 + e+ + v_e 0.02 q < 15 MeV
Relevant papers by John N. Bahcall, Sarbani Basu, M. H. Pinsonneault:
Book Recommendation - The First Three Minutes by Steve Weinberg
Big Bang Nucleosysnthesis
It is hoped that someday we will detect Big Bang neutrinos!
3. The cosmic microwave background (CMB) radiation
The early universe should have been very hot. The cosmic
microwave background radiation is the remnant heat leftover
from the Big Bang.
These three measurable signatures strongly support the notion
that the universe evolved from a dense, nearly featureless
hot gas, just as the Big Bang model predicts.
The Evidence For The Big Bang In 10 Little Minutes